[SimplifyCFG] Assertion `IterCnt++ < 1000 && "Iterative simplification didn't converge!"' failed. #155081
Description
Reproducer:
https://godbolt.org/z/a71K7znh4
int x[1024], y[1024];
int i, j;
void foo() {
for (i = 0; i < 1024; ++i) {
x[i] = 0;
for (j = 0; j < 1024; ++j)
if (!y[j])
x[i] = 1;
}
}You have to specify the following to reproduce the crash:
-O2 -mllvm -unroll-allow-remainder=false -mllvm -unroll-count=0Backtrace:
clang++: /root/llvm-project/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp:247: bool iterativelySimplifyCFG(llvm::Function&, const llvm::TargetTransformInfo&, llvm::DomTreeUpdater*, const llvm::SimplifyCFGOptions&): Assertion `IterCnt++ < 1000 && "Iterative simplification didn't converge!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0. Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang++ -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O2 -mllvm -unroll-allow-remainder=false -mllvm -unroll-count=0 <source>
1. <eof> parser at end of file
2. Optimizer
3. Running pass "require<globals-aa>,function(invalidate<aa>),require<profile-summary>,cgscc(devirt<4>(inline,function-attrs<skip-non-recursive-function-attrs>,openmp-opt-cgscc,function<eager-inv;no-rerun>(sroa<modify-cfg>,early-cse<memssa>,speculative-execution<only-if-divergent-target>,jump-threading,correlated-propagation,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,aggressive-instcombine,libcalls-shrinkwrap,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,reassociate,constraint-elimination,loop-mssa(loop-instsimplify,loop-simplifycfg,licm<no-allowspeculation>,loop-rotate<header-duplication;no-prepare-for-lto>,licm<allowspeculation>,simple-loop-unswitch<no-nontrivial;trivial>),simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,loop(loop-idiom,indvars,extra-simple-loop-unswitch-passes,loop-deletion,loop-unroll-full),sroa<modify-cfg>,vector-combine,mldst-motion<no-split-footer-bb>,gvn<>,sccp,bdce,instcombine<max-iterations=1;no-verify-fixpoint>,jump-threading,correlated-propagation,adce,memcpyopt,dse,move-auto-init,loop-mssa(licm<allowspeculation>),coro-elide,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>),function-attrs,function(require<should-not-run-function-passes>),coro-split,coro-annotation-elide)),function(invalidate<should-not-run-function-passes>),cgscc(devirt<4>())" on module "<source>"
4. Running pass "cgscc(devirt<4>(inline,function-attrs<skip-non-recursive-function-attrs>,openmp-opt-cgscc,function<eager-inv;no-rerun>(sroa<modify-cfg>,early-cse<memssa>,speculative-execution<only-if-divergent-target>,jump-threading,correlated-propagation,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,aggressive-instcombine,libcalls-shrinkwrap,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,reassociate,constraint-elimination,loop-mssa(loop-instsimplify,loop-simplifycfg,licm<no-allowspeculation>,loop-rotate<header-duplication;no-prepare-for-lto>,licm<allowspeculation>,simple-loop-unswitch<no-nontrivial;trivial>),simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>,loop(loop-idiom,indvars,extra-simple-loop-unswitch-passes,loop-deletion,loop-unroll-full),sroa<modify-cfg>,vector-combine,mldst-motion<no-split-footer-bb>,gvn<>,sccp,bdce,instcombine<max-iterations=1;no-verify-fixpoint>,jump-threading,correlated-propagation,adce,memcpyopt,dse,move-auto-init,loop-mssa(licm<allowspeculation>),coro-elide,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,instcombine<max-iterations=1;no-verify-fixpoint>),function-attrs,function(require<should-not-run-function-passes>),coro-split,coro-annotation-elide))" on module "<source>"
5. Running pass "simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>" on function "_Z3foov"
#0 0x000000000403c9d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x403c9d8)
#1 0x0000000004039e04 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4039e04)
#2 0x0000000003f7e518 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
#3 0x00007b1840442520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x00007b18404969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
#5 0x00007b1840442476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
#6 0x00007b18404287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
#7 0x00007b184042871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
#8 0x00007b1840439e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#9 0x0000000003f17ef9 iterativelySimplifyCFG(llvm::Function&, llvm::TargetTransformInfo const&, llvm::DomTreeUpdater*, llvm::SimplifyCFGOptions const&) SimplifyCFGPass.cpp:0:0
#10 0x0000000003f19262 simplifyFunctionCFGImpl(llvm::Function&, llvm::TargetTransformInfo const&, llvm::DominatorTree*, llvm::SimplifyCFGOptions const&) SimplifyCFGPass.cpp:0:0
#11 0x0000000003f19ce5 simplifyFunctionCFG(llvm::Function&, llvm::TargetTransformInfo const&, llvm::DominatorTree*, llvm::SimplifyCFGOptions const&) SimplifyCFGPass.cpp:0:0
#12 0x0000000003f19e2a llvm::SimplifyCFGPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f19e2a)
#13 0x0000000001bf010e llvm::detail::PassModel<llvm::Function, llvm::SimplifyCFGPass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x1bf010e)
#14 0x00000000039aabb1 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x39aabb1)
#15 0x00000000012268fe llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x12268fe)
#16 0x0000000002e4e9f2 llvm::CGSCCToFunctionPassAdaptor::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x2e4e9f2)
#17 0x000000000122563e llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::CGSCCToFunctionPassAdaptor, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x122563e)
#18 0x0000000002e44382 llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x2e44382)
#19 0x0000000005220ede llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::PassManager<llvm::LazyCallGraph::SCC, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5220ede)
#20 0x0000000002e4b646 llvm::DevirtSCCRepeatedPass::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x2e4b646)
#21 0x0000000005220efe llvm::detail::PassModel<llvm::LazyCallGraph::SCC, llvm::DevirtSCCRepeatedPass, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&>::run(llvm::LazyCallGraph::SCC&, llvm::AnalysisManager<llvm::LazyCallGraph::SCC, llvm::LazyCallGraph&>&, llvm::LazyCallGraph&, llvm::CGSCCUpdateResult&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5220efe)
#22 0x0000000002e490fa llvm::ModuleToPostOrderCGSCCPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x2e490fa)
#23 0x000000000122561e llvm::detail::PassModel<llvm::Module, llvm::ModuleToPostOrderCGSCCPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x122561e)
#24 0x00000000039a8c41 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x39a8c41)
#25 0x0000000005921e63 llvm::ModuleInlinerWrapperPass::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x5921e63)
#26 0x00000000050c190e llvm::detail::PassModel<llvm::Module, llvm::ModuleInlinerWrapperPass, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x50c190e)
#27 0x00000000039a8c41 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x39a8c41)
#28 0x00000000042e26a3 (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#29 0x00000000042e5d31 clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x42e5d31)
#30 0x00000000049b0313 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49b0313)
#31 0x00000000066cba0c clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x66cba0c)
#32 0x00000000049b06f8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49b06f8)
#33 0x0000000004ca6b95 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4ca6b95)
#34 0x0000000004c22d3e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4c22d3e)
#35 0x0000000004d98bc1 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x4d98bc1)
#36 0x0000000000db3c5f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdb3c5f)
#37 0x0000000000daa90a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#38 0x0000000004a186d9 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#39 0x0000000003f7e9b4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x3f7e9b4)
#40 0x0000000004a18cef clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#41 0x00000000049da9ad clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49da9ad)
#42 0x00000000049dba3e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49dba3e)
#43 0x00000000049e3675 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0x49e3675)
#44 0x0000000000db0115 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdb0115)
#45 0x0000000000c63a44 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xc63a44)
#46 0x00007b1840429d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#47 0x00007b1840429e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#48 0x0000000000daa3b5 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+++0xdaa3b5)
clang++: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134There are multiple open issues reporting the same assertion failure, but since each reproducer (including this one) appears to be a different program, I could not determine whether they are the same issue. If you determine that this is the same issue, please feel free to close this one.